The present invention relates to a valve control apparatus for an internal combustion engine, which is able to vary a lift-amount characteristic, a working angle (valve-open period) or the like of an intake valve or an exhaust valve functioning as an engine valve, in accordance with an operating state of the engine.
In the field of a valve control apparatus functioning to vary a valve lift amount or working angle of the engine valve through a rocker arm by controlling a rotation of control shaft, it is required that an operational control range of the valve lift amount or the like of the engine valve is enlarged by widely varying a swing fulcrum of the rocker arm.
United States Patent Application Publication No. 2009/0050086 (corresponding to Japanese Patent Application Publication No. 2009-47083) discloses a previously-proposed valve control apparatus. In this technique, the control shaft is integrally formed in a crank shape in order to secure a large distance between a rotation center of the control shaft and the swing fulcrum of the rocker arm.